Connecting 3 different columns with different data

Hello

I am trying to connect 3 different tables so that i can view data in a single bargraph. 

I am trying to have the maintenance graph for yearly data. All the 3 tables have different dates, different status. There is no common link between them. I tried to visualise them in a single barhraph and this is the endresult.

For plumbing its shows correct yearly data (break down for 3 years) and others its simply repeating the cumulative count of 3 years  insteadd of yearly data (i believe its because i took date from Plumbing which is not related to Mechnaical and Electrical).

I tried to create link between the due dates and it didn't work.

I have uploaded the file here https://www.dropbox.com/s/4hbo3viq2sleij2/Maintenance.pbix?dl=0 

Thanks in advance

Bishnu